Interpolymers of isobutene and acrylonitrile



Patented Jan. '19, 195i UNITED STATES, PATENT err-ice! v I 2,5373% 1 I Ut. INTERPOLYMERSOF isonuraNnANn' Acanom'mnin. Kenneth c. may, ski-6n,pad; and Robert J. Reid, Fair Lawn, N. J., ,assignors to The FirestoneTire & Rubber corporation of Ohio Company, Akron, Ohio, a

"i No Drawing. Application December-113, 1 944,

' Serial No. 568,067

This invention relates to resinous interpolymers of isobutene andacrylonitrile, andflto a process for making the same. v f

Isobutene is'obtainablein large quantities in connection with therefinement of petroleum,

and hence affords a. prospectively cheap and to provide novel and usefulpolymeric resins from isobutene and acrylonitrile.

Another object is to provide novel and useful I resinous interpolymersof isobuteneand acrylonitrile. a I r A further object is to provide suchinterpoly- I containing isobutene and acrylonitrile. 'I'he mixturesinterpolymerize smoothly. and rapidly to .yield resinous polymers havingunique propmers which have unique properties'of resistance .1 f

to solvents and oils, adapting them for use as'.'

containers and containerlinings: for a wide variety of commodities. l

I A still further object is to provide a process for the manufacture ofsuch resins.

The-above and other objects are.- secured, in

v accordance with this invention, by theinterpolymerization,. in aqueousemulsion and in the erties adapting them to varied uses, This ready,interpolymerization is surprising, in view of the impossibility ofpolymerizing unmixed' isobutene by emulsion methods, and infurth'er'view of thereluctance of isobutene to interpolymerize,'eitherin emulsion or in any other system, with the majority of compounds whichwould ordinarily suggest themselves for the pur- The proportions ofisobutene and of acrylonitrile supplied to the polymerization reactionof this invention may be varied within wide limits, bearing in mind the.fact, as will beseen hereinafter from Table I (item 1) that thereaction is retarded by any large excess of the isobutene. Likewise, theacceptance of isobutene into the interpolymer is abruptly inelastic atthe equimolecular ratio (see Table I,. of.

'items 1 and 6) suggesting a largely heteropolymeric mechanism.Accordingly, there will usually be no advantage in "employing more thanabout 75% of isobutene, on the basis of total monomers, since yieldsdrop off rapidly'above th ratio without any greatly' increased aefcep't'ance of isobutene into the, polymer. ,Like- "*"wise, increasedamounts ofjisobuteneQin the polymerization-mass result in decreasedmolecuglar 'weight'in the resinous product. However, if it is desired,for one reason or another, to force a maximum of isobutene into'thejinterpolymer, polymerizations can be conducted upon mixtures containingas high as; isobutene.

At the other end of the scale, a" useful improvepresence of .a peroxidiccatalyst, or mixtures Inent: in properties," over purepolyacrylonitrile,

3 may be obtained by the polymerization of mixtures containing as low asisobutene. The interpolymers will correspondingly contain from about 10%to about 60%, preferably from about 20% to about 50%, of the elements ofisobutene,

based on the total weight of the elements of isobutene and acrylonitrilein the interpolymer, and exclusive of any other ingredientsinterpolymerized therewith as hereinafter described.

As media for the emulsion polymerizations of this invention there may beemployed aqueous solutions of any suitable emulsifying agents, such asorganic alkali metal sulfates and sulfonates on the order of the higherfatty sulfates and sulfonates; higher fatty esters, amides, and othersof groups bearing sulfate and sulfonic groups; aromatic and alkylatedaromatic suli'onates; and the like. There may also be employed the fattyacid alkali metal soaps; cationic surface active agents such as thefatty amines and amido-amines; and non-ionic surface active agents suchas the condensed glycols and polyvinyl alcohol. The aqueous media maycontain upwards of about 0.5% and preferably from 1% to 3% of theemulsifying agents, depending on the effectiveness of the specificemulsifying agents employed, and also upon the desired state of thefinal product; thus, if it is desired that the final product shall be astable latex, more emulsifier will be employed than if a granular orlumpy product is acceptable.

In general, a sufficient amount of the aqueous emulsifying medium iemployed to provide a conveniently workable polymerization mass, thisquantity being upwards of 75%, and preferably about 100%, based ontheweight of monomers. 200% or more may be employed, but will usually befound unnecessary and wasteful of space in the reaction equipment.

Any of the usual oxygenating catalysts may be incorporated into thepolymerization mass to promote the reaction, such catalysts beingexemplified in hydrogen peroxide, per-salts on the order of potassiumpersulfate and sodium perborate, organic acid peroxides such as benzoylperoxide and peracetic acid, and other similar compounds. The amount ofcatalyst used may vary from about 0.5 to about 5.0%, based on the weightof monomers, the greater quantities resulting in higher yields in anygiven time, at the expense of some reduction in average molecular weightof the product. The use of approximately 1.0% of catalyst, based on theweight of monomers, will ordinarily be found most suitable.

The interpolymerizations of this invention may be carried out attemperatures varying from about 30 to about 80 C. At the lowertemperatures, the reaction proceeds slowly, with formation of highermolecular weight polymers and conversely, at higher temperatures thereaction proceeds rapidly with formation of polymers of somewhat lowermolecular weight. A good balance between economy of operation andquality of product will be found in a preferred range of from about 40to about 65 C. Under these conditions, the reaction will proceedsubstantially to its maximum conversion (under favorable conditions,about 70%) in approximately forty-eight hours. The unreacted monomersthen remaining may be suitably recovered and recycled.

The polymerization process of this invention may be carried out invarious types of apparatus.

Since the constituents are gaseous under the preferred conditions ofreaction, the polymerization must be carried out under pressure. For theproduction of small lots of resin, the ingredients may be scaled up in abomb or other suitable vessel, and mounted in an appropriate tumbling orshaking apparatus. Large scale operations are preferably carried on instationary autoclaves provided with suitable rotary agitating means inthe interior thereof.

In addition to simple binary interpolymers of isobutene andacrylonitrile, this invention also contemplates the production ofternary and even more complex interpolymers by the inclusion, into thepolymerization mass, of other monomers, such as butadiene, methylmethacrylate, styrene and like polymerizable unsaturated compounds. Asmuch as 50%, based on the total weight of monomers, of such extraneousmonomers, may be incorporated without interfering with the inclusion ofthe isobutene into the inter-polymer.

The interpolymers of isobutene and acrylonitrile of this invention areclear, hard, flexible and, especially where the catalyst employed is aper-salt, highly solvent-resistant. However, even the solvent-resistantmodifications are sufliciently soluble in a few convenient specialsolvents-- acetonitrile, acetone, cyclohexanone, nitroparaffins, alkylcyanides, and the likefor purposes of fabric coating, film and fibercasting, and like fabrication processes. The resins are thermoplasticand may be worked up into various products by extrusion, injectionmolding, calendering, friction-coating and other appropriate processes.Though incompatible with many of the common types of plasticizers, theresins of this invention may be satisfactorily plasticized by theincorporation of special plasticizers such as the aryl sulfonamides,nitroparaflins, aromatic nitro esters and others. The products are ofespecial use in solvent resistant containers and container linings.

With the foregoing general discussion in mind, there are given herewithdetailed examples of the practice of this invention. All parts given areby weight.

EXAMPLE I Parts Isobutene 90, 75, or 50 Acrylonitrile (correspondingly)10, 25, or 50 Aqueous emulsifying medium 100, 150, 200, or 300 CatalystAs per Table I A series of polymerizations were run in accordance withthe foregoing schedule, using the isobutene and acrylonitrile inproportions such that their mixture contained 90, '75 or 50% ofisobutene, based on the total of isobutene and acrylonitrile, andemploying the other ingredients in various combinations as indicated. Ineach run the ingredients, suitably chilled to prevent loss of volatileconstituents, were sealed up in pressure bottles, and the bottles placedin an apparatus arranged to agitate the bottles in a water bathmaintained at the temperature selected for that run. During thepolymerization, a latex dispersion of the polymer formed in the bottles,and also, in some cases, a certain amount of coagulated polymer. At theconclusion of the run, the bottles were cautiously opened, the containedlatex coagulated by treatment with ethanol, or if necessary, withhydrochloric acid, washed, and dried. Particulars of the several 76 runsare set forth in Table I.

Table I I born 2 tion Polymerization Mass (percentage: .on ReactionOonbasis or total monomers) ditions Per g r Yield Cent No, 1 CatalystAqueous Medium Per Cent u k 1 Y Temp.,- Time, tene,Per cc product Cent 1v Type Per Cent Type Per Cent H 9:2 men. 100 4o 90 '10. 7 44 90 H o 3:;'.do... 100 50 g 144 12 51v n H -8 .do. we to 43' 45.5 75 o do... 100 4p7 9o 41 76 H :1 '.do 100 so 166 v3: 40 "to H 0 :1 }..do..... 100 40 9s-1s 31 a;v 0 :1 }.;do.... 100 as 131 as as 7 to, 0.75 do 100 to e0 tobeta 1 do 150 50 17 s l 50 1 do 150 60 41 -26 '50 1 note 13.. 150 50 4126.6

to do 1 .do-- 300- 50 41 are 50 do 2 do 200 50 40 42 50 K2820; 1 150 5019 $.13 50 do do 200 50 41 55.1 75 do 1 note on 200 60 40 50 50beiitiizoyl pcrox- 1 note 200 60 40 50 Note A- 2}% aqueous solution ofmixed lauryl and myristyl sodium sulfates.

Note Bl% aqueous solution of mixed lauryl and myristyl sodium sulfates.

Note 0-27,, aqueous solution of mixed sodium oleatc and stearate.

The relative molecular weights, based on viscosity data, of the resinsobtained in run Nos. 1, 3 and 5 respectively were 27,000, 53,000 and74,000,

showing that increasing amounts of acrylonitrile less sufficientlythermoplastic for hot molding processes. The product was soluble inspecial solvents such as acetonitrile and the like.

1 EXAMPLE II Ternary interpolymer The foregoing ingredients weresubjected to the procedure of Example I. The temperature of thepolymerization was 50 C. and the polymerzation was continued forforty-nine hours. There was obtained a 57% yield of a tough, hard,thermoplastic resin.

EXAMPLE III Ternary interpolymer Parts Isobutene 34 Acrylonitrile 33Butadiene 1, 33 Potassium persulfate 0.4

Hydrogen peroxide aqueous solution) 1.0 Mixed lauryl and myristyl sodiumsulfates" 5.0 7 Water 200 The foregoing ingredients were subjected tothe procedure of Example I. The polymerization was carried out at 50C.for forty-one hours. There was obtained a yieldof a rubbery polymer.

EXAMPLE IV Parts Isobutene 50 Acrylonitrile 50 Benzoyl per xi 1 Mixedlauryl and myristyl sodium sulfates--. 2 Water 225 The foregoingingredients were charged under pressure into a stationary polymerizationautoclave provided with a rotary stirring apparatus and with a jet forthe introduction of steam into the interior of the autoclave. Thetemperature was adjusted to 50 (Land the polymerization carried onfor'forty hours with continuous stirring. At the end of this time, theautoclave was vented to a recovery system and a current of steam blownthrough the mass to sweep out the unreacted monomers. The polymerizationmass was removed fromthe autoclave, and coagulated by the addition ofalum. The coagulum was separated from the aqueous phase by filtration,washed on the filter, and dried. There was obtained a granular polymerwhich was insoluble in hydrocarbons, chlorinated hydrocarbons, alcohols,ethers, esters and ketones, with the exception of acetone. The resin wassoluble in nitromethane and other nitroparaflins. The resin wasincompatible with the usual plasticizers but was successfullyplasticized with 2-nitro isobutyl phthalate, and formed into filmswhich, by virtue of their oil resistance, were admirably adapted aswrapping materials for butter, lard, greases and the like. Paper coatedfrom an acetone solution of this resin to a dried coating thickness 01'.001" had excellent resistance to solvents and oils, suggesting the useof such coated papers as con- Eigers for 1k solvents, liquid fuels, andthe The foregoing ingredients were subjected to the process of ExampleIV. The resultant granular resin was even more highly resistant tosolvents than the resin produced in accordance with Examples IV, beinginsoluble in acetone and the nitroparaflins. The resin was, however,soluble in acetonitrile, and a flexible wrapping film suitable forpackaging butter, oils, greases, etc., was cast from such a solution.The material was thermoplastic, and an oil line fitting was compressionmolded therefrom.

From the foregoing general description and detailed examples, it isevident that this invention provides novel and useful resins which aresusceptible of fabrication by the usual procedures of hot molding,extruding, calendering, friction coating, solvent coating, film castingand the like. Although resistant to solvents in general, the resins ofthis invention are readily soluble in a few relatively cheap solventssuch as acetone, acetonitrile and the nitroparafflns, permitting them tobe used in coating compositions and to be fabricated by processesinvolving solvents. The resins may be worked up into molded articles,especially mechanical fittings which will be exposed to solvent action;cast or calendered films, especially for use as wrappings for oily andgreasy materials such as butter, lard, grease, etc.; and coated fabricsand papers for use in contact with solvents, as for instance incontainers for solvents, liquid iuels, oils and the like. The resins aremanufactured from the relatively cheap and abundant isobutene andacrylonitrile, by the use of processes which are cheaply and readilycarried out.

What is claimed is:

1. A resinous interpolymer exclusively of isobutene, acrylonitrile, andmethyl methacrylate wherein the elements of isobutene are present to theextent of from about to about 60%, based on the total weights ofisobutene and of acrylonitrile in said interpolymer, and wherein theelements of methyl methacrylate are present to the extent of not morethan 50%, based on the weight of the elements of all monomers in saidinterpolymer.

2. A rubbery interpolymer exclusively of isobutene, acrylonitrile andbutadiene-1,3, wherein the elements of isobutene are present to theextent of from about 10% to about 60%, based on the total weights of theelements of isobutene and of acrylonitrile in said interpolymer, andwherein the elements of butadiene are present to the extent of not morethan about based on the total weights of the elements of all monomers insaid interpolymer.

3. Process which comprises interpolymerizing, in aqueous emulsion, amixture solely of isobutene, acrylonitrile, and methyl methacrylate saidisobutene being present in the mixture to the extent of from about 10%to about 90%, based on the total weight of isobutene and acrylonitrilein the mixture, and said methyl methacrylate being present in themixture to the extent; of not more than 50%, based on the total weightof monomers present in said mixture.

4. Process which comprisesinterpolymerizing, in aqueous emulsion, amixture solely of isobutene, acrylonitrile, and butadiene-1,3, saidisobutene being present in the mixture to the extent of from about 10%to about 90%, based on the total weight of isobutene and acrylonitrilein said mixture, and said butadiene being present to the extent of notmore than 50%, based on the total weight of monomers in said mixture.

5. The process which comprises polymerizing, in aqueous emulsion, amixture of isobutylene, acrylonitrile and methyl methacrylate as thesole polymerizable materials, said isobutylene being present in themixture to the extent of from 20% to based on the total weight ofisobutylene and acrylonitrile in the mixture, and said methylmethacrylate being present in the mixture to the extent of 15% to 50%,based on the total weight of monomers present in said mixture.

6. An interpolymer prepared by the polymerization of a mixture ofisobutylene, acrylonitrile and methyl methacrylate as thesolepolymerizable materials, said isobutylene being present in the mixtureto the extent of from 20% to 80%, based on the total weight ofisobutylene and acrylonitrile in the mixture, and said methylmethacryiate being present in the mixture to the extent of 15% to 50%,based on the total weight of monomers present in said mixture.

KENNETH C. EBERLY. ROBERT J. REID.

REFERENCES CITED lhe following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 5 2,213,423 Wiezevich Sept. 3,1940 2,241,900 Brubaker May 13, 1941 2,376,014 Semon May 15, 1945Certificate of Correction Patent No. 2,537,626 January 9, 1951 KENNETHC. EBERLY ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requirlng correction as follows:

Columns 5 and 6, in the table, fourth column thereof, Run No. 3, percent of the Catalyst K 3 0 for 0.7; read 0.8; column 7, line 12, foramples read ample;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of th case in the Patent Ofiice.

Signed and sealed this 10th day of April, A. D. 1951.

THOMAS F. MURPHY,

Assistant Gammz'ssz'oner of Patents.

1. A RESINOUS INTERPOLYMER EXCLUSIVELY OF ISOBUTENE, ACRYLONITRILE, ANDMETHYL METHACRYLATE WHEREIN THE ELEMENTS OF ISOBUTENE ARE PRESENT TO THEEXTENT OF FROM ABOUT 10% TO ABOUT 60%, BASED ON THE TOTAL WEIGHTS OFISOBUTENE AND OF ACRYLONITRILE IN SAID INTERPOLYMER, AND WHEREIN THEELEMENTS OF METHYL METHACRYLATE ARE PRESENT TO THE EXTENT OF NOT MORETHAN 50%, BASED ON THE WEIGHT OF THE ELEMENTS OF ALL MONOMERS IN SAIDINTERPOLYMER.
 2. A RUBBERY INTERPOLYMRE EXCLUSIVELY OF ISOBUTENE,ACRYLONITRILE AND BUTADIENE-1,3, WHEREIN THE ELEMENTS OF ISOBUTENE AREPRESENT TO THE EXTENT OF FROM ABOUT 10% TO ABOUT 60%, BASED ON THE TOTALWEIGHTS OF THE ELEMENTS OF ISOBUTENE AND OF ACRYLONITRILE IN SAIDINTERPOLYMER, AND WHEREIN THE ELEMENTS OF BUTADIENE ARE PRESENT TO THEEXTENT OF NOT MORE THAN ABOUT 50%, BASED ON THE TOTAL WEIGHTS OF THEELEMENTS OF ALL MONOMERS IN SAID INTERPOLYMER.